Regulatory Matters (Summary Of Actual Capital Amounts And Ratios For The Company And Its Three Largest Subsidiary Banks) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Total capital (to risk-weighted assets), Actual Amount	$ 7,411	$ 7,450
Capital to Risk Weighted Assets	13.20%	13.90%
Total capital (to risk-weighted assets), To be well capitalized, Amount	$ 5,604	$ 5,359
Total capital (to risk-weighted assets), To be well capitalized, Ratio	10.00%	10.00%
Tier 1 capital (to risk-weighted assets), Actual Amount	$ 6,285	$ 6,811
Tier One Leverage Capital to Average Assets	9.20%	10.30%
Tier One Capital Required to be Well Capitalized	$ 3,426	$ 3,317
Tier 1 capital (to risk-weighted assets), Actual Ratio	11.20%	12.70%
Tier 1 capital (to risk-weighted assets), To be well capitalized, Amount	$ 4,483	$ 4,287
Tier 1 capital (to risk-weighted assets), To be well capitalized, Ratio	8.00%	8.00%
Common Equity Tier One Capital	$ 5,719	$ 6,245
Common Equity Tier One Capital Ratio	10.20%	11.70%
Common Equity Tier One Capital to be Well Capitalized	$ 3,643	$ 3,483
Common Equity Tier One Capital to be Well Capitalized Ratio	6.50%	6.50%
Tier One Capital	$ 6,285	$ 6,811
Tier One Capital Required to be Well Capitalized to Average Assets	5.00%	5.00%